Baron started buying Tesla about three years ago, when the stock was about $33 a share. Over time as it fluctuated, he accumulated 1.2 million shares for a total cost of $261 million. Based on Monday's close of $250 a share, his stake in Tesla was worth $302 million.

Initial purchase date

5/10/2012

Initial purchase price

$33.11

Unit cost per share over time

$218.43

Total cost to buy 1.3M shares

$282,714,299

Current market value of stake

$299,804,963

Source: Baron Capital 11/04/15

The current market value of Tesla is more than $30 billion. In four or five years, Baron said the stock could be worth $120 billion. "In 10 years, you have another triple behind that."

The electric automaker expects to sell about 55,000 units this year, with deliveries for the new Model X sport utility vehicle slated to start in the third quarter. The company hopes to sell 500,000 vehicles annually by 2020.

Stocks like Tesla and Under Armour fall into a smaller part of Baron's portfolio that he terms "open-ended opportunity investments." Israel-based Mobileye, a developer of technologies for camera-based advanced driver assistance systems, is another example, he said. "These companies are in a different league. They have dimension, extra elements."

"Safe investments make up 60 percent to 80 percent of my portfolio," Baron continued. "Manchester United is a safe investment. They are a competitive advantage business, where there are significant growth opportunities and they can double in five or six years."

Baron Stake in Manchester United (MANU)

Initial purchase date

11/15/2012

Initial purchase price

$12.74

Unit cost per share over time

$15.69

Total cost to buy 16.1M shares

$253,611,857

Current market value stake

$263,939,405

Source: Baron Capital 6/15/15

He started buying shares of ManU in November 2012, when they were trading under $13 each. Over time as the stock fluctuated he amassed 16.1 million shares for a total cost of $253 million. Based on Monday's close of $16.33 a share, his ManU stake was valued at nearly $264 million.

When he started buying the company, it was doing about "$600 million in revenues and making $150 million a year."

"We think in five or six years," he continued, "they'll make $1 billion [or] $1.1 billion [in revenue] and they'll do about $400 million or $500 million in cash flow … and the stock will be trading at $40."

Manchester United of the English premier league is one of the most popular soccer clubs in the world. But Baron doesn't see the value of the stock as just the team. "As opposed to people thinking about it as a rich man's toy, we think about it as a television program."

Comparing the viewership for a ManU game to that of the Super Bowl in the U.S., which drew 114 million viewers this year, he said ManU does about "40 games a year, where each of those games has viewers of 40 million people."